Methods and challenges of a dementia prevalence study
NZSA2024
Claudia Rivera-Rodriguez, PhD
Demonstrated that a prevalence study was feasible in Māori, Chinese, Indian and Pākehā
We found that the sampling/doorknocking strategy was reasonable
We were able to train up multi-ethnic interviewers
Response rate at the door-knocking stage was 75% but at subsequent stages was about 25%
Aim: Establish the true current prevalence of dementia in NZ
Population: Chinese, Indian and Pākehā 65yo+
This talk presents the sampling design and lessons learned from the IDEA study
There is separate study for Māori(running at the moment too)
Phase 1
Stratified by TA and rurality
Oversampling of Chinese/Indian(65+) dense areas
Phase 2
A proportion of meshblocks is sampled from each area selected at phase 1
Sampling of meshblocks is proportional to the density of Chinese and Indians.
Phase 3
We decided on a margin of error of about 0.03,
Meshblocks with only businesses, not residential dwellings: We replace these with the closest meshblock (based on selection probability) from the same area.
Door-knocking is expensive and difficult.
Training of interviewers in 4 different languages
Consent rates vary across ethnicities: Sampling weights will need adjustment for this.
Data processing from questionnaires in four different languages.